config-validator

A checker for KrakenD configuration files, which describe how an API gateway routes requests to backend services. It checks syntax, supported features, configuration patterns, and KrakenD Community versus Enterprise Edition compatibility.

In plain words
What is it for?
Use it to check a new or existing configuration, diagnose JSON errors, verify edition compatibility, or validate Flexible Configuration files.
Why use it?
It identifies configuration errors and explains where and how to fix them instead of leaving you to interpret vague failures.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/krakend/claude-code-plugin/config-validator
Any agent
npx skills add krakend/claude-code-plugin --skill config-validator
Clone the repo
git clone --depth 1 https://github.com/krakend/claude-code-plugin

Made for: Claude Code, Codex.

Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 870 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00025 $0.00870
Opus 5 $0.00013 $0.00435
Sonnet 5 $0.00005 $0.00174
Haiku 4.5 $0.00003 $0.00087

Measured 2d ago against content hash 39583cec13b7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

config-validator scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/config-validator/SKILL.md · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

KrakenD Configuration Validator

Purpose

Validates KrakenD configurations with specific error fixes, edition compatibility checks, anti-pattern detection, and automatic Flexible Configuration support with actionable feedback.

When to activate

  • User asks to validate a KrakenD configuration
  • User mentions "check config", "validate krakend", "is this valid", "config errors"
  • User has JSON syntax errors in krakend.json
  • User wants to verify CE vs EE compatibility

What this skill does

Validates JSON syntax with specific line/column error reporting, checks edition compatibility (CE vs EE features), detects configuration issues using smart three-tier validation (native → Docker → schema), auto-detects Flexible Configuration (CE and EE variants), and provides specific fixes with exact locations and documentation links.

CRITICAL: Anti-Hallucination Rules

YOU MUST FOLLOW THESE RULES - NO EXCEPTIONS:

DO:

  • Only fix errors explicitly listed in validation output
  • Read the guidance field in every validation result (contains binding instructions)
  • Search KrakenD documentation when uncertain about syntax
  • Trust validation output as authoritative

DON'T:

  • Suggest fixes based on assumptions, patterns, or intuition
  • Add corrections that aren't in the error list
  • Guess syntax based on patterns from other systems
  • Add fields that "should be there" without validation saying so

Example:

  • ❌ WRONG: Validation says "unknown field: 'backend'" → You suggest "backends" (hallucination)
  • ✅ CORRECT: Validation says "missing field 'timeout'" → You suggest adding timeout

KrakenD-Specific Quirks

Flexible Configuration: CE uses .tmpl files with Go templates (requires FC_ENABLE=1, FC_SETTINGS env vars). EE uses flexible_config.json (auto-detected, no env vars). Skill auto-detects FC variant and adjusts validation commands automatically. Schema: Always use versionless https://www.krakend.io/schema/krakend.json Docker/Edition: CE uses krakend image, EE uses krakend/krakend-ee image (requires LICENSE file) Validation Tiers: Native krakend check (most accurate) > Docker > JSON Schema

Read the full file on GitHub · 70 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 70 lines · 25 tokens per session scan A 39583cec13b7

Subscribe to this mod's changes

config-validator is a skill published in the GitHub repository krakend/claude-code-plugin (3 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 25 tokens to every session and 870 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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